Along its considerable length, the Mississippi River presents many appearances.  Its headwaters, in the glacial lakes of Minnesota, produce a modest stream that gradually widens as it travels south.  Tumbling over St. Anthony’s Falls at Minneapolis, then passing the bluffs of Iowa, the river gathers volume and width, pressing toward its confluence with the Missouri (at St. Louis) and, further downstream, the Ohio (at Cairo, Illinois).  When the flow reaches the flatlands of Louisiana, its broad, sheetlike surface belies a swift and treacherous current, racing toward discharge into the Gulf of Mexico through a weblike array of channels. 
 

The city of New Orleans owes its existence—and its economic viability—to its location near the mouth of the Mississippi.  For centuries, the river has acted as the primary conduit for the consumer goods, natural resources, and agricultural products that make New Orleans one of the world’s greatest ports.  Lake Pontchartrain to the north and the Gulf of Mexico to the south further enhance the city’s stature as a hub of travel, trade, and recreation.  Yet periodic flooding, tropical storms, and vanishing wetlands are ever-present reminders of instability.  Surrounded by water, the city is also surrounded by risk.  And still, New Orleans perseveres.
 

Surrounded by Water: New Orleans, the Mississippi River, and Lake Pontchartrain, currently (Jan. - Sept. 2008) on view in the Williams Gallery, offers a wide-ranging view of the city’s environmental history.  Maps, photographs, and memorabilia document centuries of dependence on—and modifications of—our watery environs. 
 

Through much of the 19th century, shipping on the Mississippi River was hindered by a variety of obstacles—those fixed firmly in the mud (snags), those bobbing on the surface (sawyers), and others, including sandbars, that were not always visible from the river pilot’s vantage point.  The modern U.S. Army Corps of Engineers, formed in 1802, was charged with the task of building and maintaining America’s navigation canals and coastal defenses.  An 1824 act of Congress “to improve the navigation of the Ohio and Mississippi rivers” extended the Corps’ mandate to include the removal of obstacles such as snags and sandbars from the nation’s major rivers.  In Louisiana, the Corps focused its efforts on the breakup of the Great Red River Raft, an impenetrable logjam blocking the Red River—a tributary of the Mississippi—to the north of Natchitoches in the late 19th century. 
 

One of the Mississippi River’s worst obstacles lay at the river’s mouth, where a constant buildup of silt created bars sizable enough to render the pass unnavigable. By the 1860s the problem was so serious that deep-draft ships were frequently blocked from approaching New Orleans, forcing captains to seek other ports. In the late 1870s engineer James B. Eads (1820–1887) designed a series of jetties at South Pass which allowed silt to be deposited beyond the continental shelf, ending bar-related navigation problems at the pass. Eads’s jetties, and the promise of a year-round navigation channel, sparked a shipping boom in ports along the river. 
 

Another “hazard” for navigators was the ever-shifting course of the river itself.  Charles Pike’s 1847 “ribbon map” supplied the names of land owners and the location of their plots along the Mississippi corridor from Port Hudson, a small town north of Baton Rouge, to New Orleans. Similar maps produced for river pilots—often in book form—provided pertinent updates on the river’s changing course.  Replete with extensive commentary on adjacent lands, the bound versions of these maps functioned not only as navigational aids but also as travel guides. 
 

During the last quarter of the 19th century, the Corps stabilized the course of the Mississippi from St. Louis to Minneapolis, ensuring predictable navigation between the two river ports. A variety of manmade structures—wing dams, revetments (concrete embankments), weirs, and locks—produced a mostly predictable navigation route and diminished the effects of natural features like rapids, bars, multiple channels, and snags.
 

Since the great Mississippi River flood of 1927, the Corps has taken on an increasingly central role in flood protection—constructing levees, spillways, and other structures designed to protect America’s urban and natural resources. One of the greatest challenges currently facing the Corps is the maintenance of the Old River Control Structure some 100 miles upriver from New Orleans. A complex of locks and dams, the structure prevents the Mississippi from meandering west, capturing the Atchafalaya River, and bypassing New Orleans.
 

The Mississippi River constantly seeks the shortest route to the Gulf of Mexico and threatens to abandon its channel below Baton Rouge. Since the 1950s, a series of dams and spillways on the Red and Old rivers have allowed some water to pass into the Atchafalaya Basin, while holding the Mississippi to its current path—flowing past New Orleans, south through Plaquemines Parish, and out into the Gulf of Mexico. After the great flood of 1927, engineers increasingly relied on spillways to divert floodwaters in a controlled fashion. The Bonnet Carré Spillway, about 25 miles upriver from New Orleans, became operational in 1931 and has been opened several times to protect the city from floods.  
 

While the Corps wrestled with the Mississippi River, New Orleans maritime interests sought avenues for utilizing Lake Pontchartrain’s economic potential.  A waterway between the Mississippi River and Lake Pontchartrain long stood as the holy grail of these interests. Such a route, it was understood, would enhance access to the Gulf of Mexico while bypassing the treacherous obstacles of the lower Mississippi.  In 1794 the Spanish governor, Baron Francisco de Carondelet (1748–1807), authorized the construction of a canal—known as the Carondelet or Old Basin Canal—between the bayou and what is now Basin Street.  Its purpose was to permit ship-borne cargo to be brought to the “back door” of the city. Shallow depth and a narrow channel limited the canal’s efficacy, and a few decades later a new watercourse was proposed.

The New Basin Canal was built in the 1830s along the route now occupied by the Pontchartrain Expressway, about a mile west of the Old Basin Canal.  Both canals were an integral part of the city’s port system, their banks lined with warehouses storing lumber and bricks, produce and seafood. The opening of the Industrial Canal in 1923 diminished the older canals’ importance and resulted in their closure. The Old Basin Canal was filled in during the 1920s; the New Basin Canal was filled in, in stages, between the late 1930s and late 1950s.
 

The Old and New Basin canals provided an open water route to the center of the city for certain low-draft vessels, but a proposed canal link to the river—down present-day Canal Street—was never built. The Inner Harbor Navigation Canal, known locally as the Industrial Canal, was constructed between 1912 and 1923. With the extension of the Intracoastal Waterway through eastern New Orleans in the 1940s, a navigable shortcut to the Gulf finally became feasible. The Mississippi River Gulf Outlet, or MR-GO, was completed in 1963. So long anticipated, MR-GO has become a lightning rod for controversy. The outlet is currently slated for closure, due to unexpected problems with silt build-up; the constant expense of dredging; and the belief that MR-GO funneled hurricane surge into both Orleans and St. Bernard parishes during hurricanes Betsy and Katrina.
 

Ecological and economic concerns have coalesced to prompt federal and state efforts to protect the city from flooding and sustain the fragile wetlands. Likewise, early 20th-century land reclamation projects along Lake Pontchartrain’s southern shore, and population increases on both shores of the lake, have altered the ecological balance.  The recognized need to reestablish the lake as a healthy, multi-use resource has energized both the public and private sectors.  Surrounded by Water celebrates the human spirit—the industry and the artistry—that allows us to be borne, and continually reborn, upon the water.  
 

Free and open to the public, Surrounded by Water opened January 26 and continues on view through September 20, 2008.  The exhibition is open Tuesday–Saturday, 9:30 a.m.–4:30 p.m., and Sunday, 10:30 a.m.–4:30 p.m., at 533 Royal Street.

—Pamela D. Arceneaux, John H. Lawrence, John Magill